The present and foregoing application claims priority to Japanese Patent Application No. P2000-155704 filed May 26, 2000. All of the foregoing applications are incorporated herein by reference to the extent permitted by law.
1. Field of the Invention
The present invention relates to magnetic recording apparatuses and magnetic recording methods for recording data on magnetic tapes, and more particularly relates to a magnetic recording apparatus and a magnetic recording method for recording digital data in a plurality of recording formats having different recording track widths.
2. Description of the Related Art
Recently, consumer-oriented and professional-oriented digital video recorders for recording digitized video data and audio data on magnetic tapes have become available for use. A digital video (DV) format is a known recording format for such digital video recorders. The DV format is a standard which is mainly used for consumer-oriented digital video recorders that use a 6.35 mm (xc2xc inch)-width video tape. Recorded data includes frame image data obtained by compressing and encoding each frame of an input image, audio data, and system information. Since recording signals are compressed and the recording density is increased, high-quality, long-time recording is achieved compared with a conventional system. The DVCADM format, which is based on the DV format, is adapted mainly for professional use, and it is used for the same type of video tape having a width of 6.35 mm.
When using a DV-formatted video tape and a DVCAM-formatted video tape by a video tape recorder and player having two magnetic heads which are placed on a rotating drum at opposing positions of 180 degrees, the rotating speed of the rotating drum is 9000 rpm, the tape feeding speed is 18.831 mm/s in the DV format and 28.247 mm/s in the DVCAM format, and the recording track width is 10 (m in the DV format and 15 (m in the DVCAM format.
Recording apparatuses capable of recording in the two formats, namely, the DV format and the DVCAM format, have been developed. Since the recording track width is different in each format, it is necessary to mount recording heads dedicated for the recording track width in each format. As a result, the configuration and a control system become complicated, and the production cost is thus increased.
Accordingly, it is an object of the present invention to provide a magnetic recording apparatus capable of recording data in different recording formats using a smaller number of components.
It is another object of the present invention to provide a magnetic recording method for recording data in different formats using a smaller number of components.
According to an aspect of the present invention, the foregoing objects are achieved through provision of a magnetic recording apparatus for recording data on a magnetic tape, which includes a magnetic-tape running unit for running the magnetic tape. A running-speed control unit controls the running speed of the magnetic tape. A rotating and driving unit which has a cylindrical shape rotates at a constant speed and at a predetermined angle with respect to the running direction of the magnetic tape. A data writing unit, which is provided on a cylindrical surface of the rotating and driving unit and which is rotated, scans the magnetic tape at a predetermined angle and writes data while always overwriting data in a lateral portion of an area written by the previous scan.
According to the magnetic recording apparatus, the data writing unit is rotated at a constant speed by the rotating and driving unit. An area of the magnetic tape written by each scan always includes a lateral portion of an area written by the previous scan. In this overlapping portion, old data is overwritten by new data, and writing continues. The width of an area excluding the overwritten portion varies in accordance with the running speed of the magnetic tape. The running-speed control unit controls the running speed, thus changing the recording track width. It is therefore possible to record data in a plurality of recording formats, without providing a data write unit for each recording track width.
According to another aspect of the present invention, the foregoing objects are achieved through provision of a magnetic recording method for recording data on a magnetic tape, which includes the steps of scanning the magnetic tape by a magnetic head which rotates at a constant speed and at a predetermined angle with respect to the running direction of the magnetic tape and writing data while always overwriting data in a lateral portion of an area written by the previous scan; and controlling the running speed of the magnetic tape in order that the width of a portion other than the overwritten portion of the written area has a predetermined value.
According to the magnetic recording method, the rotating speed of the magnetic head is constant. An area of the magnetic tape written by each scan always includes a lateral portion of an area written by the previous scan. In this overlapping portion, old data is overwritten by new data, and writing continues. The width of an area excluding the overwritten portion varies in accordance with the running speed of the magnetic tape. By controlling the running speed, the recording track width can be changed. It is therefore possible to record data in a plurality of formats, without providing a recording head for each recording track width.